967 resultados para Lithium aluminate
Resumo:
Group 4 complexes containing diphosphinoamide ligands [Ph2PNR](2)MCl2 (3: R = Bu-t, M = Ti; 4: R = Bu-t, M = Zr; 5: R = Ph, M = Ti; 6: R = Ph, M = Zr) were prepared by the reaction Of MCl4 (M = Ti; Zr) with the corresponding lithium phosphinoamides in ether or THF. The structure of [(Ph2PNBu)-Bu-t](2)TiCl2 (3) was determined by X-ray crystallography. The phosphinoamides functioned as eta(2)-coordination ligands in the solid state and the Ti-N bond length suggests it is a simple single bond. In the presence of modified methylaluminoxane or i-Bu3Al/Ph3BC(C6F5)(4), catalytic activity of up to 59.5 kg PE/mol cat h bar was observed.
Resumo:
The electrochemical behavior of alpha-Keggin-type nanoparticles, Co(en)(3)(PMo12O40) (abbreviated as PMo12-Co), have been studied in poly(ethylene glycol) for four different molecular weights (PEG, average MW 400, 600, 1000, and 2000 g mol(-1)) and containing LiClO4 (O/Li=100/1) supporting electrolyte. The diffusion coefficients of the PMo12-Co nanoparticles were determined using a microelectrode by chronoamperometry for PEG of different molecular weights that were used to describe the diffusion behavior of PMo12-Co nanoparticles in different phase states. Moreover, the conductivity of the composite system increases upon addition of PMo12-Co nanoparticles, which was measured by an a.c. impedance technique. FT-IR spectra and DSC were used to follow the interactions of PEG-LiClO4-PMo12-Co, and well described the reason that the PMo12-Co nanoparticles could promote the conductivity of the PEG-LiClO4-PMo12-Co system.
Resumo:
Compounds of Sr4Al14O15: Eu were prepared in air atmosphere by high temperature solid state reaction. The reduction of Eu3+--> Eu2+ was firstly observed in the aluminate phosphor of Sr4Al14O25: Eu synthesized in air condition. This made aluminate a new family and Sr4Al14O25 a new member of compounds in which Eu3+ ion could be reduced to Eu2+ form when fired in air atmosphere. The reduction of Eu3+ --> Eu2+ in Sr4Al14O25: Eu was explained by means of a charge compensation model. Experiments based on the model were designed and carried out, and the results supported this model.
Resumo:
Lanthanocene chlorides (C4H7OCH2C9H6)(2)LnCl[Ln=Y(1); Ln=Gd(2)] were synthesized by the reaction of tetrahydrofurfurylindenyl lithium(in situ) with corresponding anhydrous lanthanide chorides in THF. The crystal structures of these two complexes were determined by X-ray diffraction and they were unsolvated monomeric complexes. They were stable in the air for several hours. Complexes 1 and 2 belong to the same crystal system (orthorhombic) and space group(P2(1)2(1)2(1)). The unit cell dimensions of complex 1 were a=1.042 52(9) nm, b=1.47455(12) nm, c=1.497 99(13) nm, Z=4, D-c=1.508 g/cm(3); The unit cell dimensions of complex 2 were a=1.037 01(10) nm, b=1.472 33(12) nm, c=1.513 54(14) nm, Z=4, D-c=1.699 g/cm(3). They have the same structure and different space configurations. The central metal atom is coordinated by two indenyl, two oxygen of the tetrahydrofurfuryl and one chlorine atom to form a distorted trigonal bipyramid.
Resumo:
Reaction of anhydrous ytterbium trichlorides with 2 equiv. of cyclopentylindenyl lithium in THF solution, followed by removal of the solvent MO. crystallization of the product from diethyl ether, affords a crystal complex of the composition (C5H9C9H6)(2)Yb(mu-Cl)(2)Li(Et2O)(2). Crystallographic analysis shows that the ytterbium coordinated by two cyclopentylindenyl rings and lithium surrounded by two ether molecules are bridged by the two chlorine atoms and Yb, U and two chlorine atoms form a plane.
Resumo:
A series of compounds, La2/3 - xLi3xMoO4, were first prepared. Their structures are tetragonal scheelites with the cationic defects. The cell parameters a, c and values of c/a decrease with the increasing of the substitution amount (3x) of lithium ion. Cationic vacancies are getting more as Li+ concentration is lower. The diffusion of lithium ion is predominant. The concentration of charge carriers increases with increasing the substitution amount (3x) of lithium ion, meanwhile, the concentration of cationic vacancies decreases. The conductivity approaches the best when the substitution amount (3x) of lithium ion is about 0.3. The conductivity of La0.567Li0.3MoO4 is 6.5 x 10(-6) S . cm(-1) at room temperature.
Resumo:
The history of solid state electrolyte, the categories, ion transport mechanism, characterization, and the methods to raise the ionic conductivities of polymer electrolytes are reviewed. The further required attentions in the development of polymer electrolytes are discussed in the final part of the review.
Resumo:
Reaction of anhydrous lanthanide trichlorides with tetrahydrofurfuryl indenyl lithium in THF afforded bis(tetrahydrofurfurylindenyl) lanthanocene chlorides complexes (C4H7OCH2C9H6)(2) LnCl, Ln = Nd (1), Sm (2), Dy (3), Ho (4), Er (5), Yb (6). The X-ray crystallographic structures of all the six complexes were determined and these indicate that they are unsolvated nine-coordinate monomeric complexes with a trans arrangement of both the sidearm and indenyl rings in the solid state. They belong to the same crystal system (orthorhombic) and space group (P2(1)2(1)2(1)) with the same structure. Especially, they are more stable to air and moisture than the corresponding unsubstituted indenyl lanthanide complexes.
Resumo:
A droplet of aqueous solution containing a certain molar ratio of redox couple is first attached onto a platinum electrode surface, then the resulting drop electrode is immersed into the organic solution containing very hydrophobic electrolyte. Combined with reference and counter electrodes, a classical three-electrode system has been constructed, Ion transfer (IT) and electron transfer (ET) are investigated systematically using three-electrode voltammetry. Potassium ion transfer and electron transfer between potassium ferricyanide in the aqueous phase and ferrocene in nitrobenzene are observed with potassium ferricyanide/potassium ferrocyanide as the redox couple. Meanwhile, the transfer reactions of lithium, sodium, potassium, proton and ammonium ions are obtained with ferric sulfate/ferrous sulfate as the redox couple. The formal transfer potentials and the standard Gibbs transfer energy of these ions are evaluated and consistent with the results obtained by a four-electrode system and other methods.
Resumo:
The crystal of complex [Li(THF)(4)][Fe(S2C2B10H10)(2)(THF)] 3 belongs to monoclinic, space group P2(1) with a = 11.964(2), b = 16.527(3), c = 12.554(3) Angstrom,beta = 108.70(3)degrees, V= 2351.3(8) Angstrom(3), Z = 2, M-r = 835.95, D-c = 1.181 g/cm(3), mu (MoKalpha) = 5.30 cm(-1), f(000) = '874, R = 0.0622 and Rw 0.1538 for 1641 observed reflections with I > 2sigma(I). The ionic complex,of 3 contains the square pyramidal anion of [Fe(S2C2B10H10)(2)(THF)](-) and the tetrahedral cation of [Li(THF)(4)](+). The iron is 5-coordinated and located in the square pyramidal configuration. The iron atom and the four sulfur atoms are almost coplanar. The Lithium atom is coordinated with four oxygen atoms of four THF molecules and located in a tetrahedral configuration.
Resumo:
The interaction between polyaniline (PAn) and 2,5-dimercapto-1,3,4-thiadiazole (DMcT) was investigated by means of cyclic voltammetry and UV-visible spectroscopy. The results show that the polymerization-depolymerization reaction of DMcT or its dilithium salt Li(2)DMcT is a kinetically quasi-reversible process. PAn exhibits very weak electrochemical activity in neutral propylene carbonate. After doping with protonic acid, such as hydrochloric acid or maleic acid etc., however, it shows an extensively enhanced electroactivity. For the complex system, PAn-DMcT or PAn-Li(2)DMcT, polyaniline has no catalytic activity for the electrochemical polymerization-depolymerization reaction of DMcT or DMcT(2-). Instead, the enhancement of the electrochemical redox activity of PAn-DMcT system compared with that of PAn, DMcT, Li(2)DMcT, and PAn-Li(2)DMcT comes from the protonic doping of PAn by DMcT.
Resumo:
Reaction of YbI2 with two equivalents of cyclopentylindenyl lithium (C5H9C9H6Li) affords ytterbium(II) substituted indenyl complex (C5H9C9H6)(2)Yb(THF)(2) (1) which shows high activity to ring-opening polymerization (ROP) of lactones. The reaction between YbI2 and cyclopentylcyclopentadienyl sodium (C5H9C5H4Na) gives complex [(C5H9C5H4)(2)Yb(THF)](2)O-2 (2) in the presence of a trace amount of O-2, the molecular structure of which comprises two (C5H9C5H4)(2)Yb(THF) bridged by an asymmetric O-2 unit. The O-2 unit and ytterbium atoms define a plane that contains a C-i symmetry center.
Resumo:
Rare earth complex (C5H9C9H6)(3)SmCl-Li+ (THF)(4)( I ) was synthesized by reacting anhydrous SmCl3 with two equivalents of C5H9C9H6Li. From mix-solvent of THF and hexane, red color single crystals were obtained. The crystal belongs to a cubic system, space group P2(1)3 with unit cell parameters a= b=c= 1. 754 0(2) nm, alpha=beta=gamma=90degrees, V=5. 396 4(11) nm(3), Z = 4. The ten-coordinated samarium atom is bonded to three cyclopentylindenyl rings and a chlorine atom to form the anionic part of the title complex, ring centroids and the chlorine atom form a tortured tetrahedron around samarium. In the cationic part, lithium atom coordinates to four oxygen atoms of THF molecules to form a normal tetrahedron. The Sm-C(within the same ring) distance varies from 0. 268 to 0. 299 nm.
Resumo:
The effects of plasticizer ethylene carbonate (EC) on the AC impedance spectra and the ionic conductivity are reported. With increasing of EC concentration the semicircle in high frequency disappears, and the slope of the straight line in low frequency decreases. The data obtained from impedance experiments can be explained using an equivalent circuit proposed. On the other hand, the room temperature conductivity increases with EC concentration because of the increase of the segmental flexibility of PEO. For lower EC concentration samples, the temperature dependence of conductivity in low temperature range follows Arrhenius type, but when EC concentration is larger than 20%, the temperature dependence of conductivity obeys the Vogel-Tamman-Fulcher (VTF) equation in all temperature ranges.
Resumo:
(C5H9C5H4)(3)NdBrLi(THF)(4)(1)(C5H9=cyclopentyl) was obtained from the reaction of NdCl3 with C5H9C5H4Na and LiBr (Nd:Na:Li=1:2:1 molar ratio) in THE X-ray crystallography showed that the ten-coordinated neodymium atom is bonded to three cyclopentylcyclopentadienyl(eta(5)) rings and a single bromine atom bridging a lithium which is bonded to three THF molecules. Complex 1 is triclinic, P1 space group with unit dimensions of a= 12.048(2), b= 13.498(3), c= 13.831(3)Angstrom, a = 104.16(3), beta = 104.07(3), gamma =95.96(3)degrees, V=2083.3(7)Angstrom(3), Z=2, D-c=1.35Mg/m(3) and F(000)=874. (C5H9C5H4)(3)SmTHF (2) was synthesized by reaction of anhydrous SmCl3 with C5H9C5H4Na at a molar ratio of 1:3. The structure was determined by X-ray crystallography. The ten-coordinated samarium atom is bonded to three cycloperrtylcyclopentadienyl rings and one oxygen of THF molecule to form a pseudo-tetrahedron. Complex 2 is orthorhombic, Fdd2 space group with unit cell dimensions of a =28.175(5)Angstrom, b =46.24(2) Angstrom, c =9.167(4) Angstrom(3), V=11943(8)Angstrom(3), Z= 16, D-c = 1.38Mg/m(3) and F(000)=5136.